A quick question(s) to anyone who operates SMT lines with only one multi purpose flex machine (P&P). What is an ample feeder count for this machine?...and secondly, do you have a standard kit of common parts that you would wish to reside permanantly on the machine?...if so, how many of the overall feeder count would you dedicate? i.e. 150 total/50 dedicated to standard kit. (Please be reasonable--no 2000 feeder counts with 500 standard kit)

A typical machine will have around 100 feeder slots. Manufacturers use the slots differently though, use 8mm feeder counts as your basis. Siemens, for example has 40 slots but you can get 2 (or 3) 8mm's per slot giving you 80+ 8mm feeders, while a Samsung has 104 slots and you can get only 1 8mm per slot for a total of 104. The larger feeders all require varying space depending on the manufacturer. And of course other option like tray feeders typically take away from your feeder capacity. I think what you need to do is take a look at the common parts between your BOM's and their normal run quantity. Also, you need to consider how much room you will need for your uncommon parts, your product with the most feeder space required for uncommon parts will be your constraint.

Sorry, I did misunderstand. My opinion would be: Assuming nothing else used feeder space, like tray changers, camera's, nozzles, ..... and assuming 1 slot = 1 8mm feeder position, I think 70-90 slots would be reasonable. A reasonably priced feeder table quick change over mechanism would be ideal for about 75% of the slots. The remainder of the slots would be fixed for common parts like bypass cap's, pull down resistors and other high placement count part numbers. The 25% common parts should also be located in the best position for the pick-n-place sytstem to realize maximum throughput.

Thanks for the response k_h, A few follow up questions... 1. 70-90 slots seems low for a one machine line. What is the maximum number of different parts on your worst case job? 2. Could the common parts be adressed by being assigned as "point of use parts"? This way they would not be included in the job kit. 3. What do you do currently with these common parts? If you have feeder carts they would come off the machine with the carts and then they would have to be put back onto the machine thus increasing changeover time.

72 different part numbers, 53 being 8mm, remainder being 12-44mm and 3 tray. It may be low but anymore than 100 and you give up throughput because of feeder locations. And thinking about it, 70-90 is low for a low volume high mix line. I guess if I wasn't interested in speed more feeders would be fine. I would need around a 100 slots to fit my 72 part numbers. "point of use" I don't understand? We don't kit parts, we have a seperate inventory space for the parts the machines use right next to the line. I have two machines with 4 feeder tables, two of the tables are fixed with common parts and the other two are feeder carts. It works well for us. The bad thing about fixed common parts is that you can not optimize the locations so you have to do as much planning ahead of time as possible.

"Point of use" could be your common high runner parts. They are sometimes kept next to the machines (at the point of use) and may be categorized seperately from the rest of the inventory. In your case all of your parts are inventoried next to the machine. Sorry to bother you again... Is that one fixed feeder table per machine or both on the same machine? Do feeders on both sides of the line create kitting problems? How do you balance the workload between machines?

Thinking about it, if I was designing machines and based on my experience I would offer a high feeder count, high flexibility machine and low speed. In addition another machine with low feeder count, not flexible (8mm parts) and high speed.

Each machine has two feeder tables, one is fixed, the other interchangable. Parts on both sides of the machines does not create a kitting problem but can be inconvenient for feeder replenishment. I have found "U" shaped lines to be much more operator friendly than a straight line. I have used shuttle gate conveyors on long lines for easy access to the back of machines. We also put our high usage (common parts) on the front of the machines. We balance our feeders about every two years based on all of our BOM's at that time.

I find 100 feeder slots of 16 mm width quite sufficient. If there are two feeder tables, each table is ~ 36� wide. Even slow machines can travel that distance in less then 1.5 seconds. If I further assume, that an optimized set up may save 30-40 % of the travel time, you can calculate if you wish to re-configure your set up, or if you keep ~ 20 feeder slots in a fixed set up. If my machine places 100 components in 60 seconds optimized, or worst case 84 seconds, I save 24 seconds per board. If I run 10 boards, I save 4 minutes. If you can re-arrange all feeders in less than 4 minutes, you make more profit. For more then 10 boards it certainly makes sense to optimize the set up. These numbers are only estimates and you should experiment with your machine or optimization software to find the correct number for the average board. However, I find that you could designate 20-30 feeders with standard components ( 1k,10k... in 1206 and 0805 packages). I would rather keep these parts in feeders ( in Bliss carts, i.e. ), but not on the machine. Feeders with dual or triple tracks are quite challenging to optimize. The software tools on the machines are not always helping to speed up the machine. What good does it do, when I can save 4 minutes in production time, if the optimizer software requires 1 minute to calculate and 10 minutes to program?

The combination of a fast machine ( Chip Shooter ) and a slow, flexible machine does not seem to make sense. What, if I paid just $ 15,000 for my old CP II and it is all paid off? The feeder table has a fixed set up of all the standard components in 8 mm tapes and the machine is fine-tuned with this set up. Set up time is almost 0. I don�t care, if the machine waits for the flexible machine. If I don�t manufacture in CA with $$$ real estate, I don�t mind the space the machine is taken either. However, it takes significant time off from my flexible machine.

Hello Stefan, Thank you for your reply. I see now that manufacturers are aware that this kind of thought process is necessary for the bottom line profit. It is also true that one can be "seconds wise and minutes foolish" in the process. I read with great interest your reply as you makes points for and against a standard kit of common parts. I have trouble deciphering which side of the fence you are on. A couple of questions... 1. You say 100 slots of 16mm width. I assume this means up to 100 8mm or 12mm tapes. Correct? 2. You also say you would prefer the 20-30 standard components not to be resident on the machine. Why? 3. Is the work environment in this case (LVHM) to hectic to know whether or not it makes sense to move around (optimize) the feeders for higher throughput? Could this not be determined ahead of time off line (perhaps with some software)? 4. Are you saying chipshooters will be utilized in LVHM environment? Will their availability and low cost (pre-owned) outweigh their shortcomings?

1. Not quite. The width of 16 mm came most likely from the reel width, which can be up to 15 mm wide for the 8 mm tape. The reel for the 12 mm tape is up to 18 mm wide and would occupy already two slots. If you design a machine from scratch, I would consider to stagger the reels that a 12 mm feeder could also sit in a 16 mm slot. 2. I usually optimize the set up or recommend my customers to optimize and therefore remove the feeders from the machine. 3. I only see small LVHM houses. Most of them are hectic, most of them can not effort third party software. However, this is now even more complicated. If you tie more than one job together and try to find an optimized set up for all these jobs together, you will definitely loose money on all jobs. 4. Yes, this is just my opinion. If I can buy an FCM for $ 50,000 i.e., I get certainly my biggest bang for the buck.

P.S. I did promote the fixed set up in my Fuji CP II sample, because the machine with feeders did cost as much as an extra feeder table (without feeders)from Siemens. The Fuji places 7000 comp./per hour. The extra feeder table saves me a few minutes a day and may pay off in three or four years.

I currently am doing it. Keep in mind the parts are split up, such that, the chips are on one machine and the IC's and odd parts are on the second. It takes much more time to place IC's and odd parts because they need to be handled slower and often come from a tray or stick feeder which is slower. In the end, for an example, you can place 20 parts on the chip shooter and 10 on the flexible machine in the same amount of time on both. I have 2-fixed and 2-changeable tables, my high running programs have the machines running within a few seconds of eachother.

I know, it can be done and I participated in many acceptance tests, in which we counted even the milliseconds. However, my vision had a bit shifted, since the time the Motorola�s and Flextronic�s dumped all these high volume machines to the market. It makes quite some difference to me, if my $ 300,000 Siplace performs 100 % or if I paid only $ 30,000 for it and I am happy if it does only 50 %. If I run two machines side by side, I�m faster and more effective, than with any number of change over tables, which are rare and expensive even on the used machine market. The Siplace S 20 was certainly not made for the prototype market and the line computer software is not very user friendly (mildly speaking). For the price of a used machine, I would not think twice to put it in front of a flexible machine in a LVHM environment and simply not care, if it is 10 or 20 seconds waiting to convey the board to the next machine. It appears the LVHM market is all what is left here (US), when these forenamed companies took off to China. Let�s put our heads together and try to make some money with the machines these companies left behind.

Sorry, I got carried away. Kitting and standard set up make sense for some and not for others.